To make sauce, heat oil in a saucepan, add onion and garlic and cook gently until softened. Stir in tomatoes and their juice, tomato puree and chilli powder. Simmer, uncovered for 10 minutes. Remove from heat and puree in blender until smooth. Return to the heat, add chopped chilli and simmer for a further 15 minutes. Season with salt and pepper.

Cut meat into 1 inch cubes and coat with flour. Salt and pepper then quickly sear in a hot oiled pan.